1. Field
The disclosure generally relates to accessing remote storage devices and particularly to accessing remote storage devices over Remote Direct Memory Access (RDMA).
2. Description of the Related Art
Storage systems in general and block based storage systems are a key element in modern data centers. These systems are designed to retrieve and store large quantities of data. Effectiveness and usefulness of these systems are based upon several criteria and characteristics. The following are some of the characteristics:
(a) The bandwidth of data transfer or throughput, both for retrieve operations and for store operations. This is also often called transfer speed.
(b) The latency until data transfer commences, both for retrieve operations and store operations.
(c) The number of operations per second achievable in the system, both for retrieve operations and store operations.
(d) The system wide storage space, i.e., the amount of data the system can store.
(e) The size scalability of the system, which governs the ability of changing the size of the storage system during its life cycle. A scalable system is one which permits starting with a small system relative to its maximum size and altering its size with ease, as necessary, with limited penalty. Usually penalties are related to performance degradation or system downtime. Another aspect of this characteristic is linearity in scale vs. cost.
(f) The connectivity scalability of the system, which governs the ability of the system to retain its main characteristics whether accessed by a small number or a large number of clients.
There is an ongoing trend of improvement of storage systems with respect to all of these characteristics. This is a result of an ongoing market need and appreciation for such improvements.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Similarly, the above-mentioned criteria and characteristics are not necessarily known to those skilled in the art. Therefore, unless otherwise indicated, it should not be assumed that any of the information described in this section qualify as prior art merely by virtue of their inclusion in this section. Similarly, issues identified with respect to one or more approaches should not assume to have been recognized in any prior art on the basis of this section, unless otherwise indicated.